New Zealand adults (and probably children) consume more dietary sugars than recommended by World Health Organisation

The cost of sugar

Obesity costs New Zealand NZ$ 624,000,000 per annum (last calculated in 2006) [1]. This is likely to be higher now as New Zealand has the third highest rate of obesity in the OECD – trailing behind the United States and Mexico.

These unnecessary healthcare costs come from the obesity-associated non-communicable diseases being type 2 diabetes and cardiovascular disease, gout and some cancers. More people die from non-communicable diseases (11.4%) than tobacco-related deaths (9.1%) and both are largely preventable. Life expectancy may have increased in the last 100 years but over the years gained 20 – 30% are lived in poor health [2].

Obesity is not an easy topic as there are many variables behind carrying too much weight. The drivers of obesity include diet, physical activity levels, maternal health (yes, your mother’s health during pregnancy), sleep and the obesogenic environment, where food supply and marketing promote high energy intake with energy-dense and nutritionally poor foods [3], [4].

New Zealand children

Obese children are likely to grow into obese adults. As well as the adult risks later in life, obese children have their own special health consequences: obstructive sleep apnoea, musculoskeletal problems, asthma and psychological problems (body dissatisfaction, poor self-esteem and depression) are all associated with child obesity. Additionally, their learning can suffer and they may be targeted for bullying [5].

Rates of obesity are higher in our Pacific and Maori children

Eleven out of 100 NZ children (2-14 years) are obese and another 21 (out of the same 100) are in the overweight category. Rates are higher in Pacific and Maori children – 61% and 44% respectively are overweight or obese [4].

What is even more disconcerting is 50% of parents of obese children do not believe their child is overweight – this is higher in obese children aged 2-4 years where 90% of parents do not consider their child to be neither under- or overweight [6]. This is another story!

High sugar intake is one of the determinants of a poor diet and a contributor to obesity. One-quarter of sugar in a child’s diet comes from sugar-sweetened beverages [7], which are of low nutritional quality leading to a poor diet, weight gain and associated risks. The consumption of high sugar food generally displaces the consumption of more nutritious foods and increases the energy intake.

The American Heart Association (AHA) has a more cut and dry nutrition recommendation of fewer than six teaspoons of added sugar per day for children 2-18 years.

Since 1989, World Health Organisation (WHO) has strongly recommended1 children reduce their dietary intake of free sugars to less than 10% of total energy intake (<10% EI) and in 2015 suggested a further reduction of free sugars to below 5% of total energy intake (<5% EI) [8]. This is a conditional recommendation2 and is based on very low-quality evidence where a dose-response between reduced free sugar intakes of <5% EI and reduced dental caries was observed. No evidence of harm has been identified with reducing free sugars to <5% EI [8].

The strong WHO recommendation to restrict free sugar intake to <10% EI is based on moderate quality evidence3 being [8]

A meta-analysis of five randomised controlled trials with interventions to encourage children to reduce their sugar intake in food and beverages. The quality of the evidence was moderate but without effect in four of the five studies i.e. no changes in weight loss, this was likely to be due to low compliance by the study participants (children) willing to follow the dietary advice intervention [9].

A meta-analysis of prospective cohort studies did find associations with one or more servings of sugar-sweetened beverages per day and overweight or obese children [8], [9].

An effect of reducing or increasing sugar is dose dependent with regards to body weight – more sugar, higher BMI [8].

The evidence for the effect of increasing free sugar intake on body weight in children is of low quality [8].

Observational studies have found moderate quality evidence for a positive association between dental caries and sugar intake [8], [9], regardless of exposure to fluoride [8].

This is where it all becomes tricky, what exactly is ‘sugar’ – total, free or added? MOH describe sugar as monosaccharides and disaccharides. WHO talk about ‘free sugar’ and AHA refer to added sugar. Sometimes when comparing sugar it is not quite ‘apples’ to ‘apples’ but more a generalisation and you need a feel for the situation

And do we meet the guidelines?

The University of Sydney recently evaluated the free sugar intake of the Australian population (10) and the University of Otago has done the same for New Zealand adults (11). The graph, below, shows the average free sugar intake as a % of energy is higher than the WHO recommendation for all age groups except 51-70 year olds.

The average “free” sugar intake for the Australian and New Zealand populations is primarily higher than the recommended intake (<10% EI) from World Health Organisation

Australian children’s (2-14 years) mean intake of free sugars was between 11.5 and 13.8 of total EI. New Zealand does not have a free sugar intake calculated for NZ children. My rough calculation of children’s free sugar intake, based on the 2002 Nutrition Survey for Children, was an average of 12% for boys and girls aged 2-14 years4 – higher than the recommendation but a formal study is required as my data was old and limiting. Perhaps it is time for another Children’s Survey.

So now what?

Awareness of what is in our foods is key – excess sugar is associated with excess body fat, NZ children are consuming too much sugar, obese children become obese adults and obesity is associated with non-communicable diseases.

Nutrition research is in its infancy and WHO feels more research is required to evaluate different behavioural-change approaches to help promote the reduction of free sugars in children thus creating higher compliance rates in randomised controlled trials [8].

I cannot wait that long and feel that we are all in this together and need to take personal responsibility with regards to our (and our children’s) sugar consumption. Is it necessary to regularly buy sweet treats for our children – is this an act of love?

Footnotes

1. A strong recommendation from WHO suggests the desirable outcome from the recommendation outweigh any undesirable outcome 2. There is less certainty between the benefits and harms or disadvantages of implementing this recommendation still requires debate 3. Moderate quality of evidence = moderately confident that the true effect lies close to the estimate effect ut there is a possibility that it could be substantially different. Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate 4.Based on the median daily (total) sugar intake for NZ children (127 g for boys and 115 g for girls), 51% and 50% was from beverages, sugar and sweets, biscuits, cakes, desserts and cereals, which equates to 65 and 58 grams and my estimate of free sugar intake. Using a median energy intake of 9.1 MJ for boys and 7.8 MJ for girls from the same study, my estimated ‘free sugar’ consumption for both NZ boys and girls is 12% of energy.
Sugar produces 16.7 kJ per gram .. 65 g of sugar produces 1085.5 kJ (65 * 16.7) of energy .. this equates to 12% of total energy intake (1085.5/9100).